personnel for our tests, allowing us a more realis-
Workshop
The workshop is enclosed in a module of
tic setup. Early morning temperatures approached
20C, much closer to the 50C expected at the
similar construction to the generator module. Sec-
tions of the two side walls have Trombe walls built
Pole. Due to the way the snow mound was formed,
in to utilize passive solar heating. The work-
however, the pile was much warmer and the snow
shop contains a lathe, mill/drill, small welding
very wet once the outer 50 cm was penetrated.
machine, a hydraulic hose-making setup, miscel-
Some problems surfaced almost immediately. The
laneous hand and power tools, spare parts and
conveyance system was still being overwhelmed,
hardware (stored in metal cabinets), and the base
as the chips were being fed in slugs rather than in
station for the radio. Although cramped, the
a metered or steady state. Huge current surges oc-
workshop can be a welcome relief from the cold
curred when the 30-kW drive motor lugged while
and wind on the surface. A hazardous materials
trying to process these slugs. Adjustment of the
cabinet within the workshop is used for storing
soft-starter helped somewhat, but the cause of the
lubricants for the machinery associated with the
problem remained. Several strategies were tested
project.
to resolve the problem, including bleeding in air
at the snowblower, choking flow at the impeller,
further reducing impeller vane size, choking flow
at the fan, and using a dustpan arrangement in-
TESTING
stead of a snowblower for collecting chips, but
Prior to shipment of the system to Antarctica,
none yielded satisfactory results. Because the snow
tests were conducted at CRREL and the nearby
was very wet (water was running out from be-
Dartmouth Skiway in Lyme, New Hampshire.
neath the pile) we postulated that system perfor-
These tests were designed to check out the equip-
mance would improve at the Pole with the drier
ment operation, determine operating parameters,
snow and lower temperatures.
optimize systems, and check the viability of the
The hydraulic system was simplified when
overall concept. Although the vastly different
many of the functions originally designed into the
snow conditions and temperatures lessened the
system were found to be unnecessary. Hydraulic
value of the tests, they proved very useful in the
oil temperatures were extremely high, sometimes
exceeding 90C. Running without the guarding
initial refinement of the equipment design.
The tests at CRREL were the first tests of the
helped but didn't alleviate the problem. Again, this
integrated system. A small pile of snow was
was attributed to the higher temperatures encoun-
scraped up for feed material, and the equipment
tered in New Hampshire. Finally, an extender was
was set up from that point. A scissors lift was
fabricated and installed between the snowblower
rented for elevating the fan to the 9-m maximum
and extension frame to better address the debris
design lift height, and the expanding tubes ex-
pile in front of the tunneler. Tests with the drill
tended to their full length to simulate maximum
system, including the 1-m backboring bit, were
transport distance. Although snowing at the time
fully successful.
of the tests, the temperatures were 45C higher
The equipment was returned to CRREL and
than those we would encounter at Pole. The snow
modifications made as a result of the tests con-
was quite wet and we experienced some plugging
ducted. The hydraulic system was extensively
of the tubes. Some problems with the tube exten-
modified and somewhat simplified, although the
sion were encountered, but these were attributed
usefulness of some functions still needed evalua-
to inexperience and overfeeding at the front end
tion. Testing was conducted in a large, low-tem-
by the snowblower. The fan initially performed
perature facility at CRREL, which indicated that
poorly, so the drive was sheaved down and per-
high startup torques due to high oil viscosities at
formance improved substantially. However, some
low temperature may occur. Significant problems
lugging of the motor was still experienced. The
that still persisted included high hydraulic tem-
impeller blades of the tunneler snowblower were
peratures, inefficiencies in the chip conveyance
reduced in size to cut down on the overfeeding of
system, and bogging of the fan motor. Final reso-
the conveyance system.
lution of these problems was left for Antarctica
Tests at the Dartmouth Skiway were more rig-
where the system could be tested under design
orous, allowing a better evaluation of the system.
conditions. The equipment was prepared for ship-
A large mound of snow was generated by Skiway
ment and left CRREL in August of 1993.
14
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